The 5 Best Air Purifiers, According to Our Testing
Clean indoor air can be hard to come by, as pollutants such as smoke, mold, bacteria, pollen, and toxins all battle to infiltrate the air we breathe. Air filtration has become more relevant than ever, and an air purifier is one of the easiest and most effective ways to bring the fresh air back into your home.
We put 38 of the best air purifiers through a series of tests in our Lab, assessing them based on their design, noise levels, features, effectiveness, and overall value. For expert tips on buying and using air purifiers we spoke with Kenneth Mendez, CEO and president of the Asthma and Allergy Foundation of America, and Dr. John McKeon, CEO of Allergy Standards.
"People spend more than 90 percent of their time indoors, and indoor air can be two to five times more polluted than outdoor air," says Mendez. "Indoor air is made up of tiny particles—including animal dander, pollen, mold, dust mites, and fumes released by cooking, burning fuel, or cleaning products—that can trigger asthma and allergies. Air purifiers can improve your home's indoor air quality by reducing indoor air pollution or removing airborne allergens."
Our top pick is the Levoit Core 400S Air Purifier because it is extremely effective at filtering both particulate matter (PM) and volatile organic compounds (VOCs), or harmful chemicals that can be emitted from a variety of household products. Plus, it's Wi-Fi enabled and moderately priced in comparison to other smart air purifiers.
Keep scrolling for more of our top air purifier picks, and find expert tips for buying air purifiers and improving your indoor air quality.
Our Top Picks
- Best Overall Air Purifier: Levoit Core 400S Air Purifier
- Best Budget Air Purifier: Toppin Comfy Air C2 Air Purifier
- Best Air Purifier for Allergies: Bissell air400 Air Purifier
- Best Air Purifier for Pets: RabbitAir MinusA2 Ultra Quiet Air Purifier
- Best Air Purifier for Smoke: Dyson Purifier Cool Purifying Fan TP07
Our top pick is the Levoit Core 400S Air Purifier because it is extremely effective at filtering both PM, such as smoke, as well as VOCs, specifically those emitted from household products. It's also Wi-Fi enabled, so you can connect it to your phone or smart home device—a particularly advanced feature given the moderate price of this machine.
Our Testing Process
We rounded up 38 of the best-rated air purifiers and put them through a series of tests in our Lab. To start, our testers timed how long it took them to assemble the air purifier from the moment they opened the box, taking note of how clear the instructions were to follow.
Next, we evaluated the design of each air purifier, based on the build quality, aesthetics, design features, and footprint. Our testers then used a decibel meter to record the noise levels of each air purifier on its highest and lowest setting and took note of how noisy it sounded to them, too.
For air purifiers with additional features, such as air quality indicators or Wi-Fi compatibility, we tested these functions and recorded whether they were useful and simple to navigate on the first try.
The real test of each air purifier was its effectiveness at purifying the air. We set up indoor greenhouses, or "air quality testing chambers," and recorded the baseline particulate matter (PM) and volatile organic compound (VOC) levels. We tested each air purifier's ability to filter particles in the air by emitting incense smoke and pet hair into the chamber and zipping it closed. Once the incense smoke was extinguished, we measured the PM in the chamber, waited another 10 minutes, and measured it again. We then repeated this test in the highest mode.
To test the ability of the air purifier to filter VOCs, we placed a bowl containing 4 ounces of mothballs in the testing chamber, and allowed them to permeate the area for at least 15 minutes. Prior to running the air purifier, we measured the initial level of VOCs in the air. We then ran the air purifier on its lowest mode in the chamber for 10 minutes, recording the VOC level every five minutes. We repeated this testing process on the air purifier's highest mode of operation, too.
Finally, testers received the price of the air purifier, and were asked to score its overall value based on both its price and performance in our testing.
How to Shop for Air Purifiers Like a Pro
Some filters are better suited than others at filtering out different types of pollutants (such as dust, smoke, pet dander, etc.), so be sure that whichever air purifier you choose uses a filter that will best fit your needs. All of the air purifiers on our list feature a combination of at least two different types of filters, in order to provide the best indoor air quality possible. Here's a quick guide to the most common types of filters used for air purifiers:
HEPA Filters: HEPA stands for high efficiency particulate air, and is the most common type of filter used in air purifiers. These are the most efficient at filtering particles in the air, such as mold, pollen, or dust, making them ideal for those with asthma or allergies, as well as pet owners: "An air purifier with a high-efficiency particulate air (HEPA) filter is recommended for pet owners, as they remove 99.97 percent of allergens and pollutants as small as 0.3 microns from the air," says Mendez. "A HEPA filter can capture your pet's dander and fur, but it is important to change the filter regularly, so as not to release the particles back into your home." In general, HEPA filters should be replaced rather than cleaned, usually around every six to 12 months, but always refer to the manufacturer's guidelines for a specific filter.
Activated Carbon Filters: Activated carbon (or charcoal) filters are pieces of carbon treated to be very porous, which makes them ideal for filtering smoke or odors. They can absorb many contaminants in the air that HEPA filters cannot, including volatile organic compounds (VOCs). Oftentimes, activated carbon filters are used in conjunction with HEPA filters to trap both allergens and unwanted odors or contaminants. In general, you'll want to replace activated carbon filters every three to six months.
Prefilters: Many air purifiers come with prefilters to trap large debris and dirt. Oftentimes these filters are washable, making them more environmentally-friendly and cost effective than other types of filters. In order for them to remain effective, you have to clean them regularly and allow them to dry fully before reinserting them—even a small amount of water left in the filter can lead to mold growth and worsen your air quality.
It's important to consider the size of the space you want to purify. An air purifier that is too powerful for your space will use excess electricity, while a too-small air purifier won't clean the air effectively. "Don't be tempted to run an air purifier with internal doors open, to try to clean the air in a whole home," says McKeon. "If the air purifier is not designed for that large space, it will not be effective. It's better to use an appropriate air purifier for the room or two that you spend the most time in, for example the bedroom or main living space."
Most air purifiers will list the maximum square footage they are able to clean. You can calculate the square footage of your space by multiplying the room's length by its width.
The effectiveness of an air purifier is measured in clean air delivery rates (CADR), which indicates the cubic feet per minute (CFM) of purified air that an air purifier can produce on its maximum setting. CADR measures an air purifier's effectiveness for three different pollutants—pollen, dust, and smoke (although not all manufacturers list it by category). "If the CADR rating is too low for your room size, it will be ineffective," says Mendez. "The higher the CADR, the more particles the air cleaner can filter and the larger the area it can serve." According to the Association of Home Appliance Manufacturers, the CADR of your air purifier should be equal to at least two-thirds of your room size.
Even the most effective air purifier is not worth living with if the noise level is unbearable, especially considering they're meant to run all day long. We used a decibel meter to record the decibel levels at the lowest and highest settings. Most devices have a decibel level somewhere between 20 and 60.
Most air purifiers come with extra features designed to improve the user experience, although these don't make a difference in their ability to purify air. Here are a few bonus features to look out for:
- Wi-Fi Compatibility: There are plenty of air purifiers out there that can be connected to Wi-Fi and controlled via an app on your phone or smart home devices, such as Google Assistant or Amazon Alexa.
- Remote Control: This simple accessory allows you to control your air purifier without getting up, which is particularly helpful if your air purifier is going in the bedroom.
- Filter Change Indicator: Some devices feature a light that will turn on when it is time to replace the filter.
- Air Quality Indicators: An air quality indicator can alert you to changes in your home's air quality and show you how close your space is to being purified.
- Multi-Function Air Purifiers: Some air purifiers double as humidifiers, fans, or even heaters, helping to replace multiple devices in a single appliance.
Air purifiers that are Energy Star certified must meet energy-efficient specifications set by the Environmental Protection Agency, which help to save you money in the long term.
More Air Purifiers to Consider
Dyson Purifier Humidify+Cool Formaldehyde: Although this unit was the most expensive out of all the air purifiers we tested, it does double as a humidifier and a fan, so you can streamline the number of appliances in your space. Plus, it was very effective at clearing the air of contaminants during our testing.
Winix 9800 Air Purifier with Wi-Fi & PlasmaWave Technology: For large spaces, this air purifier can clean up to 2,420 square feet, and was very effective at purifying the air in our testing. However, it didn't suck up the pet hair very well, so pet owners should keep this in mind.
Levoit Core Mini Air Purifier: For small spaces such as a bedroom or home office, the Levoit Core Mini offers effective air purification for up to 178 square feet of space. We love that it has a tiny footprint and can be neatly tucked away on a nightstand or desk. Plus, it's extremely quiet on the lowest setting so you can sleep undisturbed.
Questions You Might Ask
What do air purifiers do?
Most air purifiers—including the types we tested—work the following way: A fan sucks in air, which then moves through a filter where particles are captured (most air purifiers feature an additional filter for absorbing odors and gasses). The newly cleaned air is then pumped back into the room.
"Air purifiers are designed to remove small particulate matter (a type of air pollution) from the air
we breathe," says McKeon. "These small particles can vary in size, and can irritate the lungs or trigger allergic reactions when inhaled. Primary sources of particulate air pollution include cooking, automobile emissions, dust, fires or burning of coal and other materials. Some larger particles are filtered through your nose hairs while smaller ones are not."
Where is the best place to put an air purifier?
This depends on your needs. If you have an area in your home with a strong odor, place the air purifier as close to the contaminant as possible. If your air purifier is going in the bedroom, place it on a nightstand or table close to your head, so the clean air has a shorter distance to travel before it reaches you. Avoid placing an air purifier in a tight space or against the wall, as this can block air intake. You should clear your air purifier's path from obstacles such as furniture, because they can prohibit the air flow.
How long should you run an air purifier?
To keep your air free of allergens and other contaminants, it is recommended that you run your air purifier for at least 12 hours a day, but preferably all 24 hours a day. Air can become contaminated within a few hours of turning off an air purifier.
How do you clean an air purifier?
If your air filter has a prefilter, you should clean it monthly by rinsing it off or wiping it down (refer to the manufacturer's instructions). If the prefilter is not washable, you can gently vacuum the debris off. Replace disposable air filters as often as the manufacturer recommends.
Take Our Word for It
This article was written by Melanie Fincher, associate commerce editor for Real Simple with nearly three years of experience writing product reviews and lifestyle content. Melanie is a cat owner and suffers from seasonal allergies, so she's always on the lookout for ways to improve her indoor air quality. To compile this list, we tested 38 air purifiers in our Lab and evaluated them based on their setup, design, noise level, features, effectiveness, and overall value. Melanie also received expert tips on buying and using air purifiers from Kenneth Mendez, CEO and president of the Asthma and Allergy Foundation of America and Dr. John McKeon, CEO of Allergy Standards.
What Is Real Simple Selects?
Next to each product on this list, you may have noticed a Real Simple Selects seal of approval. Any product appearing alongside that seal has been vetted by our team—put through tests and graded on its performance to earn a spot on our list. Although we buy most of the products we test, sometimes we do get samples from companies if purchasing a product ourselves isn't an option. If that's the case, we test the product just like we test anything we buy, but we also disclose that we received it for free to be as transparent with you as possible.
Love our recommendations? Check out more products that have earned the Real Simple Selects, from humidifiers to cordless vacuums.